Use polynomial as function

I'm pretty new to Mathematica but I'm pretty sure there's an easy way to do it, yet I can't figure it out: if I create a polynomial using InterpolatingPolynomial or similar functions and assign it to a varia开发者_JAVA百科ble (let's call it Poly), how can I transform it in a function callable via

Poly[5]

to obtain the value of the polynomial at x=5? I know I can use

Poly /. x->5 

for this, but for what I'm doing next I really need Poly to be a callable function.

Here is another way:

fPoly = Function[x, Evaluate[Poly]]

Evaluate[...] is required since Function[...] "holds" its arguments. Alternatively, you can use

fPoly = Function @@ {x, Poly}

In this latter approach, the head Function isn't applied until after Poly evaluates.

Found out, it was actually really easy:

fPoly = Function[k, Poly /. x -> k];

If you have:

k = InterpolatingPolynomial[{{-1, 4}, {0, 2}, {1, 6}}, u]  

Then

poly[x_] := k /. u -> x